1. Field of the Invention
The invention relates generally to non-volatile memory devices. More particularly, the invention relates to hot-carrier non-volatile memory devices with enhanced performance.
2. Description of the Related Art
In addition to resistors, diodes, capacitors, conventional field effect transistors and conventional bipolar transistors, semiconductor circuits now routinely also include non-volatile memory devices. Non-volatile memory devices are often employed in applications that require permanent, or at least semi-permanent, digital data storage. Such non-volatile memory devices are particularly desirable for providing permanent or semi-permanent digital data storage within the context of applications such as but not limited to digital imaging applications.
A particular type of non-volatile memory device that has relatively recently evolved within semiconductor fabrication technology is a hot-carrier non-volatile memory device, which is typically a semiconductor device. Hot-carrier non-volatile memory devices are generally predicated upon accelerated hot-carrier impact ionization into electron-hole pairs and injection into designated charge capture and trapping material layers. Hot-carrier non-volatile memory devices are desirable insofar as they are predicated upon conventional and well-characterized hot-carrier phenomena that under certain circumstances may become more prevalent as semiconductor device dimensions and semiconductor structure dimensions downwardly scale. Notwithstanding, hot-carrier non-volatile memory devices may be undesirable under alternative circumstances where reliable operation of a particular hot-carrier non-volatile memory device requires an increased hot-carrier non-volatile memory device operating voltage.
Various hot-carrier non-volatile memory devices are known in the semiconductor fabrication art.
For example, Wong et al., in U.S. Pub No. 2004/0007732 and U.S. Pat. No. 6,717,203, teaches a hot-carrier non-volatile memory device that is highly scalable. This particular hot-carrier non-volatile memory device includes a lateral bipolar transistor as a charge injector for injecting electrons from a semiconductor substrate into a floating gate that is located over and separated from the semiconductor substrate within the hot-carrier non-volatile memory device.
In addition, Jang, in U.S. Pub. No. 2004/0087096 and U.S. Pat. No. 6,730,957 teaches a hot-carrier non-volatile memory device that is compatible with logic devices. This particular hot-carrier non-volatile memory device includes a particular dielectric layer located interposed between a spacer and a semiconductor substrate as an electron capture and retention material.
Further, Hong et al., in U.S. Pat. No. 7,112,490, and Swift in U.S. Pat. No. 7,112,490 each teach a hot-carrier non-volatile memory device that is fabricated within a trench within a semiconductor substrate. These particular hot-carrier non-volatile memory devices use a discontinuous storage element layer conformally lining the trench but not filling the trench, and a conductor spacer located upon the discontinuous storage element layer as a control gate.
Due to the possibility of ease in fabrication, and also the existence of a mechanism of operation that is predicated upon a generally well-characterized hot-carrier injection phenomenon, hot-carrier non-volatile memory devices are likely to be of continued importance as semiconductor technology advances. For that reason, desirable are hot-carrier non-volatile memory devices with enhanced performance, and methods for fabrication of those hot-carrier non-volatile memory devices with enhanced performance.